[RE-wrenches] NEC 230.46 spliced and tapped conductors

Wed Feb 1 19:22:52 PST 2023

We've transitioned from using supply-side taps to using Feeder taps re: 
705.12(B) almost exclusively.

The advantages are numerous - and you just added one more - not needing 
line side listing on your tap hardware.

One of the most dangerous things I see looming in the present code is 
the fact that supply side taps can be safe for backfeeding up to 160 
Amps of PV on a standard 200 Amps service IF you are only grid-tie and 
the current is canceling incoming current.

But as soon as you add hybrid inverters and batteries.  Now you are 
adding significant battery charging amperage  to the NEC 220 load calcs 
that the service entrance connectors are based on..  Given that many 
residences utilized the downsize table for service entrance conductors 
you can quickly end up with a situation where your supply side tap is 
overloading your service entrance conductors if pulling the inverters 
full capability for battery charging and adding that to your normal 
house loads.

Feeder taps take care of this vulnerability in the present code.  By 
having a main 200 Amp breaker on both sides of the tap as per 705.122 B 
- all conductors are protected for both the increased loads due to 
battery charging as well as being able to still use the full 160 Amps 
available for backfeed.  And you don't have to shut down the utility to 
install.

Now you also add not needing to list your taps for supply side and you 
can use the venerable ILscos again . . .

Hope that helps!

Best,

Jeff

> Brian Mehalic via RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
> February 1, 2023 at 7:18 PM
> The requirements for power distribution blocks (PDB) to be marked 
> “*suitable for use on the line side*…” when installed connected in 
> that manner in wireways (Art. 376) and pull/junction boxes (Art. 314) 
> have been in the NEC® for quite a few cycles.
>
> It looks like the additions to 230.46 in the 2020 NEC® (PDBs and 
> splices/pressure connectors connected to service conductors must be 
> marked “suitable for use…”) coincided with this explicit requirement 
> being removed from 314 (though it remains in 376); this makes sense - 
> if you’re using a PDB on the line side, well you’re connecting to some 
> type of service conductors, so why not cover it in Art. 230 (maybe 
> it’ll also be removed from 376 in 2026).
>
> UL 1953 allows for PDBs (UL product code QPQS) to be listed for 
> connection on the line side, load side, or both, with those that can 
> connect on the line side having the marking mentioned above. Note that 
> many have an SCCR of 10 kA unless combined with 
> the manufacturer-specified fuse type and size (or smaller), and have 
> minimum enclosure sizes that must be followed as well. I have had a 
> difficult time finding PDBs that are marked for use on the line side 
> while just using the internet (and have been too lazy to pick up the 
> phone thus far...plus it doesn't help that all PDBs have a line and 
> load side of the device regardless of whether or not they are being 
> connected on the line or load side of the service!).
>
> Of course many folks are not going to want to use PDBs due to 
> re-routing conductors to them (if even possible) and having to shut 
> down the utility supply to install them. Enter pressure connectors, 
> and the seemingly industry-fave insulation-piercing style; 
> unfortunately I'm not aware of any that are available *yet* with the 
> proper listing and markings as required by 230.46.
>
> A colleague that works for a large electrical product manufacturer 
> passed this along:
>
> /“No test existed for qualifying single polarity connectors suitable 
> for line side use when this was added to the 2020 code with the 
> January 1, 2023 date for enforcement.  A strategy and test procedure 
> needed to be developed and adopted by the UL CSDS working group.  Not 
> a speedy process.  Long story short, after developing a strategy, 
> public comment period and voting the *standard wasn’t published until 
> August of last year.*  On average the testing requirements take about 
> 90 days.  To further complicate matters, I was recently told that UL 
> is still developing the submittal process.
>
> I know that there are a lot of companies currently testing products 
> but until the UL submittal process catches up, no one will be 
> official.  The *UL product code is ZMWW*; as companies become 
> qualified they should show up in the ZMWW search.  As of today, no one 
> is listed.  This leaves power distribution blocks as the lone 
> connector product rated for line side use.  I know that Bussmann has 
> some PDBs rated for line side use."
>
> So this begs the question of whether or not NEC® 90.4(D) can be 
> invoked (new products not yet available at the time the Code is 
> adopted...); PDBs already exist, so no dice there, and it is likely 
> that since they exist, an argument using 90.4(D) in regards to 
> pressure connectors/splices will fall on deaf ears because, well, use 
> PDBs."/
>
> Ugh.
>
> Brian Mehalic
> NABCEP Certified Solar PV Installation Professional™ R031508-59
> National Electrical Code® CMP-4 Member
> (520) 204-6639
>
> Solar Energy International
> http://www.solarenergy.org
>
>
>
>
>
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> Jason Szumlanski via RE-wrenches 
> <mailto:re-wrenches at lists.re-wrenches.org>
> February 1, 2023 at 6:25 PM
> As someone who does 75%+ supply-side interconnections, this kind of 
> terrifies me. We have another year of NEC 2017 here, so I have time to 
> prepare, but I'm watching this closely.
>
> Meter disconnects/reconnects here are difficult due to the lack of 
> good utility company cooperation and the requirement for an inspection 
> prior to reconnection, which leaves homeowners without power for many 
> hours at times. Otherwise, I would just pop in a 200A main disconnect 
> between the meter and main distribution panel and do a feeder tap for 
> the inverter output between the new service disconnect and the 
> existing distribution equipment. Unfortunately, that usually means 
> bringing grounding electrodes and conductors up to current standards, 
> but that's how we would be forced to comply if this splice/tap rule 
> comes into effect here and there are no suitable products available.
>
> Side note: 200A 2-pole fusible disconnects are all but impossible to 
> get here. Even 200A main breaker enclosures are very hard to find. 
> Hurricane Ian didn't help that with thousands of people who had their 
> service equipment under water... It has been a challenge.
>
>
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
>
>
>
>
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> August Goers via RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
> January 31, 2023 at 7:56 PM
> Hi Wrenches -
>
> Occasionally we will do supply side connection for our PV systems. As 
> of 1/1/2023 in CA, we follow the 2020 NEC 705.11 Supply-Side Source 
> Connections section. Recently, an inspector asked us to comply with 
> the following:
>
>
>
> When we reached out to one supplier of insulation piercing connectors 
> (ILSCO), they responded: "We are still in testing, I just checked and 
> from what I see there are no products listed for this new requirement 
> yet by any manufacturer."
>
> Has anyone bumped into this before and/or have any proposed solutions?
>
> Best, August
> Luminalt
>
>
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